Monthly Pan Evaporation Data across the Continental United States between 1950-2001

Pan evaporation is a measure of atmospheric evaporative demand (E0) for which long term and spatially distributed observations are available from the NOAA Cooperative Observer (COOP) Network. However, this data requires extensive quality control and homogenization due to documented and undocumented station moves and other factors including human errors in recording or digitization. Station-based Pan Evaporation measurements (in mm) from 247 stations across the continental United States were compiled and quality controlled for the analysis shown in Dewes et al., 2017. This dataset reports warm season (May-October; for 21 stations the data is only available for May-September) pan evaporation with at least 20 years of data between 1950 and 2001. Both monthly values and long-term monthly averages are made available, including the climatological measure for standard deviation and coefficient of variation. Dewes et al. (2017) used this dataset to evaluate the ability of different E0 formulations – Hargreaves-Samani, Priestly-Taylor, and Penman-Monteith – to reproduce the spatial patterns of observed warm-season E0 and its interannual variability. This data is an extension of the dataset described in Hobbins (2004) and Hobbins et al. (2004) with 21 additional stations north of 41oN latitude. The extension was needed in order to include data in the North Central Climate Science Center region. For these added stations, the procedure described in Hobbins (2004) for quality control was applied, including an adjustment in the mean when documented station moves occurred, and the removal of obvious outliers. The quality control procedure for the extended dataset did not automate tests for undocumented inhomogeneities for these stations. For all stations, a visual inspection of the timeseries was used to add additional breakpoints in the data for homogenization (only two were added in the extended set), and to eliminate two stations from consideration.

蒸发皿蒸发量（Pan evaporation）是表征大气蒸发需求（E0）的指标，长期且空间分布式的观测数据可由美国国家海洋和大气管理局（NOAA）协作观测员（COOP）网络获取。然而，由于已记录与未记录的测站迁移、记录或数字化过程中的人为误差等多重因素，该数据需开展严格的质量控制与均一化处理。本数据集整合了美国本土247个测站的以毫米（mm）为单位的逐站蒸发皿蒸发量观测数据，并针对Dewes等人2017年的研究完成了质量控制；其提供了1950年至2001年间序列长度不少于20年的暖季（5月至10月，其中21个测站仅提供5月至9月的数据）蒸发皿蒸发量数据，同时包含月值与长期月均统计量，其中包括标准差与变异系数的气候学统计指标。Dewes等人（2017）曾利用该数据集评估Hargreaves-Samani、Priestly-Taylor及Penman-Monteith等不同E0估算公式复现观测暖季E0空间分布特征及其年际变率的能力。本数据集是Hobbins（2004）与Hobbins等人（2004）所发布数据集的扩展版本，新增了北纬41度以北的21个测站的观测数据，此次扩展旨在纳入北中央气候科学中心所辖区域内的观测数据。针对新增测站，研究人员采用了Hobbins（2004）所述的质量控制流程，包括在有记录的测站迁移发生时对序列均值进行校正，以及剔除明显的异常值；但针对扩展数据集的质量控制流程，并未对这些新增测站的未记录非均一性问题开展自动化检测。针对所有测站，研究人员通过对时间序列的目视检查，为序列均一化处理添加额外断点（扩展数据集中仅新增2个断点），并剔除了2个测站的观测数据。